Koichi Arinaga

Long-term results of aortic valve replacement with a small St. Jude medical valve in Japanese patients.

BACKGROUND The use of small aortic valve prostheses is still controversial because of negative effects caused by residual obstruction of the left ventricular outflow tract. This study evaluated the long-term results after aortic valve replacement with a small valve from St. Jude Medical (St. Paul, MN). METHODS Between 1980 and 1999, 221 patients underwent isolated aortic valve replacement with a 23-mm or smaller St. Jude Medical valve. The mortality rate and complications were analyzed, echocardiography was performed, and peak pressure gradient, mean pressure gradient, indexed effective orifice area, and left ventricular mass index were measured. RESULTS The follow-up rate in the 221 patients was 99.5% (maximum length, 24.1 years; mean, 10.3 years). Patients with a 19-mm valve were mainly women, older, and had smaller body surface areas. Freedom from valve-related death at 20 years was 100%, 86.0%, and 90.2% in patients with 19-, 21-, and 23-mm valves, respectively. There were no significant differences in the actuarial freedom from valve-related deaths. Echocardiography showed significantly higher peak (32.3 mm Hg) and mean pressure gradients (17.6 mm Hg) and a smaller indexed effective orifice area (0.70 +/- 0.15 cm(2)/m(2)) in patients with a 19-mm valve than in those with a 21- or 23-mm valve. Moderate prosthesis-patient mismatch was present in most patients with a 19-mm valve according to one definition; however, the improvements in ejection fraction and left ventricular mass index were significant, and functional recovery (mean New York Heart Association class, 1.3 +/- 0.5; mean specific activity scale, 5.1 +/- 0.8 metabolic equivalents) was satisfactory. CONCLUSIONS The present long-term results demonstrate that a small St. Jude Medical valve can be advantageously used in most Japanese patients because their body size is generally smaller than that of Western patients. These findings also emphasize that it is not prosthesis size per se that matters but rather the relation between body size and prosthesis size.

Impact of diabetes mellitus on outcomes in Japanese patients undergoing coronary artery bypass grafting

BACKGROUND AND PURPOSE There have been no large-scale studies on the impact of diabetes mellitus (DM) on outcomes in Japanese patients undergoing coronary artery bypass grafting (CABG). METHODS AND SUBJECTS A multi-institutional retrospective cohort study was conducted in 14 Japanese centers. All adult patients who underwent isolated CABG from 2007 to 2008 were included (n=1522, mean age: 68.5years). The definitions of DM were all patients admitted with diagnosis of DM and preoperative glycated hemoglobin (Hb) A1c≥6.5%. Univariate and multivariate analyses were performed to identify the risk of morbidity and mortality. RESULTS There were 849 DM and 572 non-DM patients. Preoperative mean HbA1c were 7.1% in the DM group and 5.7% in the non-DM group (p<0.0001). Preoperative, intraoperative, and 3-day average postoperative blood glucose (BG) were 146mg/dl, 172mg/dl, and 168mg/dl in the DM group, and 103mg/dl, 140mg/dl, and 136mg/dl in the non-DM group (all p<0.0001). Although there were no significant differences in postoperative cardiovascular events, the incidence of infection was significantly higher in the DM group than in the non-DM group (9.2% vs 6.1%, p=0.036) on the univariate analysis. The all-cause death was also relatively higher in the DM group than in the non-DM group (2.1% vs 1.1%, p=0.12), and this was likely related to infection. CONCLUSION DM patients had worse perioperative BG control, higher incidence of infection, and higher mortality than non-DM patients. These results indicate that perioperative BG control guidelines should be standardized to obtain better surgical outcomes in Japanese DM patients.

Left ventricular–right atrial communication following tricuspid annuloplasty

A 71-year-old woman was admitted for examination of a heart murmur and anemia. She had a history of mitral valve replacement and tricuspid ring annuloplasty 8 months prior to admission. A new systolic murmur was heard, and echocardiography showed a high-velocity jet originating from the left ventricular outflow tract to the right atrium and a small defect between the left ventricle and the right atrium. No periprosthetic leaks were detected in the mitral position. At operation, a communication just beneath the detached prosthetic ring at the anterior-septal commissure of the tricuspid valve, and a jet of bright red blood entering the right atrium through the defect at the atrial septum just cephalad to the commissure, were found. After removing the ring, the defect was closed using a mattress suture. In this case, the tricuspid annuloplasty ring was probably placed on the atrio-ventricular portion of the membranous septum, rather than the tricuspid annulus, at the antero-septal commissure of the tricuspid valve in the previous operation, and its dehiscence may have created a tear in the atrio-ventricular membranous septum, leading to left ventricular-right atrial communication.

Postoperative Left Ventricular Mass Regression After Aortic Valve Replacement for Aortic Stenosis

BACKGROUND Small valve size and prosthetic patient mismatch are both considered to have harmful effects on residual left ventricular hypertrophy after aortic valve replacement for aortic stenosis. In general, it is believed that the effective orifice area index of the prosthesis must not be less than 0.85 cm(2)/m(2) in order to avoid prosthetic patient mismatch. On the other hand, studies have shown that valve type and valve size had no effects on postoperative left ventricular mass (LVM). The objective of this report was to examine the relationships between patient characteristics or the prosthetic valve and postoperative LVM. METHODS To evaluate the factors that influence postoperative LVM, we formulated the hypothesis that postoperative LVM is proportional to the sum total of pressure at the prosthetic valve orifice and inner surface area of the left ventricle in systole. We present a conceptually new index for postoperative LVM and compare the index with postoperative LVM. RESULTS The results indicated a strong correlation between the new index and postoperative LVM six years after surgery (r(2) =0.67, p < 0.0001). As might be expected, LVM increased gradually as the value of the new index increased. CONCLUSIONS The results of the present study indicate that postoperative left ventricular hypertrophy can be avoided by preventing postoperative hypertension in patients without left ventricular dilatation and an effective orifice area index is greater than 0.77 cm(2)/m(2).

Infection management in a patient with a left ventricular assist device : a case report of long-term cefazolin sodium hydrate administration

A 55-year-old woman suffered from a bloodstream infection (Staphylococcus aureus), which originated from pump inflow and outflow skin exits, from 4 months after a parocorporeal left ventricular assist device (LVAD) had been implanted. In addition to local irrigation, repeated administration of a weekly unit of cefazolin hydrate was temporarily effective, but fever frequently recurred. Because short-term antibiotic administration had limited effectiveness, a much longer-term course of cefazolin was begun at 14 months post-LVAD implantation and was planned to continue until future transplantation. Unfortunately, the patient died from a cerebral embolism at 19 months after LVAD implantation; long-term consecutive cefazolin administration had suppressed the infection for over 5 months without side effects. To treat intractable LVAD-associated bloodstream infection, long-term administration of a narrow-spectrum beta-lactam drug is an effective option.

Long term results and predictors of left ventricular function recovery after aortic valve replacement for chronic aortic regurgitation.

OBJECTIVES In most patients with aortic regurgitation (AR), aortic valve replacement (AVR) improves left ventricular (LV) function, but some patients will not have favorable remodeling. Our objectives were to review long term clinical results of AVR for AR and to examine what factors affect the normalization of LV function after AVR for chronic AR. METHODS Between 1989 and 2010, 177 patients underwent isolated AVR for chronic pure AR. The patients were divided into 2 groups based on indexed end-systolic LV diameter (iESD): Group L (iESD) ≥25 mm/m(2)) (130 patients) and Group S (iESD <25 mm/m(2)) (47 patients). RESULTS There was no significant difference between groups in late mortality, freedom from cardiac-related death and rehospitalization for heart failure at late follow up after operation. At postoperative follow-up, 16% of patients had not recovered normal LV systolic function. By means of multivariate analysis, iESD and cardiac index (CI) were independent predictors of recovery of LV function and iESD >26.7 mm/m(2) and CI <2.71 l/min/m(2) were the best cut-off values. CONCLUSIONS Early and late surgical results of AVR for chronic AR were good, but for the preservation of postoperative normal LV function, AVR for AR patients should be performed before iESD reaches 26.7 mm/m(2).

Late Re-operation for Aortic and Mitral Starr-Edwards Ball Valve Prostheses

Starr-Edwards ball valves removed more than 15 years after implantation were retrospectively investigated macroscopically. Eight patients required re-operation. Valve models used in the initial operations were a non-cloth-covered valve in 2 patients and a cloth-covered valve in 6. Two patients had replacement of an aortic ball valve (model 1260 and model 2320) and 6 underwent mitral valve replacement (model 6120 in one, model 6320 in 5). The mean time to re-operation was 23.0 ± 4.8 years after implantation. Cloth wear causing significant hemolysis was observed in all cloth-covered valves, regardless of valve position. Autologous tissue growth was noted on the orifice ring and struts in both aortic and mitral prostheses. Thrombus formation was not found in any of the valves. Ball variance in silicone rubber balls was mild in the non-cloth-covered valves, even in the aortic position. The most significant problem with the cloth-covered ball valve was cloth wear. Cloth wear should always be considered when 15 years or more have passed since valve implantation. Significant hemolysis, elevation of lactate dehydrogenase values, and echocardiographic detection of transvalvular regurgitation are diagnostic of cloth wear, and are indications for replacement of a cloth-covered ball valve.

Concurrent submitral left ventricular aneurysm and an aneurysm of the sinus of valsalva: Report of a case

We herein describe a rare case of a concurrent submitral left ventricular (LV) aneurysm and an aneurysm of the sinus of Valsalva in a 65-year-old Japanese woman. The patient had a history of mitral valve replacement (MVR) for mitral regurgitation caused by a submitral LV aneurysm at the age of 58. At the time of the MVR, the orifice of the submitral LV aneurysm without thrombi was beneath the posterior leaflet, but surgical repair of the submitral LV aneurysm was not attempted. Although the patient was asymptomatic, when she underwent an echocardiogram at 65 years of age an aneurysm of the noncoronary sinus of Valsalva was detected. However, echocardiography performed before the initial operation had shown that the aneurysm of the sinus of Valsalva was coexistent with the submitral LV aneurysm. Since the submitral LV aneurysm revealed no progressive enlargement during the 7 years, patch closure of the aneurysm of the sinus of Valsalva alone was successfully performed.